3 files changed, 27 insertions, 4 deletions
diff --git a/tests/crashes/124352.rs b/tests/crashes/124352.rs
deleted file mode 100644
index e9eb4419e6a..00000000000
--- a/tests/crashes/124352.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-//@ known-bug: #124352
-#![rustc_never_type_options(: Unsize<U> = "hi")]
-
-fn main() {}
diff --git a/tests/ui/attributes/malformed-never-type-options.rs b/tests/ui/attributes/malformed-never-type-options.rs
new file mode 100644
index 00000000000..0c384be0e22
--- /dev/null
+++ b/tests/ui/attributes/malformed-never-type-options.rs
@@ -0,0 +1,8 @@
+//! Regression test for #124352
+//! The `rustc_*` attribute is malformed, but ICEing without a `feature(rustc_attrs)` is still bad.
+
+#![rustc_never_type_options(: Unsize<U> = "hi")]
+//~^ ERROR expected unsuffixed literal, found `:`
+//~| ERROR use of an internal attribute
+
+fn main() {}
diff --git a/tests/ui/attributes/malformed-never-type-options.stderr b/tests/ui/attributes/malformed-never-type-options.stderr
new file mode 100644
index 00000000000..0d2ff4881f2
--- /dev/null
+++ b/tests/ui/attributes/malformed-never-type-options.stderr
@@ -0,0 +1,19 @@
+error: expected unsuffixed literal, found `:`
+  --> $DIR/malformed-never-type-options.rs:4:29
+   |
+LL | #![rustc_never_type_options(: Unsize<U> = "hi")]
+   |                             ^
+
+error[E0658]: use of an internal attribute
+  --> $DIR/malformed-never-type-options.rs:4:1
+   |
+LL | #![rustc_never_type_options(: Unsize<U> = "hi")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
+   = note: the `#[rustc_never_type_options]` attribute is an internal implementation detail that will never be stable
+   = note: `rustc_never_type_options` is used to experiment with never type fallback and work on never type stabilization
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.